data type

The type of information that one field can store, for example, text, rich text, numbers, keywords, and time.

The characteristic of columns and variables that defines what types of data values they can store. Examples include character, floating point and integer.

There are eight primitive data types in Java; five of these represent numerical types of varying range and precision - double, float, int, long and short. The remaining three are used to representing single-bit values (boolean), single byte values (byte) and two-byte characters from the ISO Unicode character set (char).

A set of possible values, together with all the operations that know how to deal with those values. For example, a numeric data type has a certain set of numbers that you can work with and various mathematical operations that you can do on the numbers but would make little sense on, say, a string such as "Kilroy". Strings have their own operations, such as "concatenation". Compound types made of a number of smaller pieces generally have operations to compose and decompose them, and perhaps to rearrange them. Objects that model things in the real world often have operations that correspond to real activities. For instance, if you model an elevator, your elevator object might have an open_door() "method".

The representation of information according to preset specifications (e.g., plain text files, fixed length text files, HTML, TIFF, etc.)